This is a tale of two joeys:
A 7-month-old wallaby who is just emerging from its mother’s pouch…
|Wallaby joey peeks out of the pouch. Photo by Dennis Dow/Woodland Park Zoo.|
…and a nearly 4-month-old wallaroo who is giving us a whole new perspective on what goes on inside the pouch.
What we've seen will amaze you.
Let’s take a closer look at the developmental stages of the two joeys.
Wallaby Joey Emerges
You can see it still has quite a bit of developing left to do. Soon the joey will grow in a furry coat and spend more time peeking out. As we head into summer, we’ll see the baby eventually begin to take little trips outside of mom’s pouch, returning for feedings.
Inside the Pouch of a Wallaroo
Here’s where things get awesome. Another joey—a wallaroo born in January—isn’t quite at the same developmental level as the emerging wallaby joey. The wallaroo joey is still tucked away securely in mom’s pouch. But our dedicated zookeepers have been doing pouch checks during the joey’s first few weeks to keep an eye on its development and to document the little-seen earliest stages of a joey’s life.
It all starts with trust. Keepers have been working with wallaroo mom, Tullah, to get her comfortable with up-close, hands-on care. This means that when it’s time for medical exams or special care, Tullah is already at ease in the presence of her keepers. Without this early training, the pouch checks would never have been possible.
Zookeeper Wendy Gardner began the pouch checks when the joey was just under 2 weeks old, and has continued to do them about once a week throughout its development. The system is simple, but has yielded amazing results.
Step One: Yam Time
Wendy and her fellow keeper, Allison Barr, head into the wallaroo’s indoor den and offer Tullah a favorite treat—yam. Even this step took some experimenting to get right. Yams cut too small made Tullah more likely to hunch over while eating. A lengthy slice encourages her to sit up while munching, putting her in the perfect position for a pouch check.
Step Two: Opening the pouch
Step Three: Observe and Document
While Wendy holds the pouch slightly open, Allison snaps photographs and the two observe the joey’s latest developments. They are looking to see that it is growing steadily, and also tracking what has changed. For example, fingers that were a fleshy blob at first started to become distinct digits in later weeks, and by day 55, keepers could see little nails forming on the fingers.
Shedding new light on these earliest stages of development will ultimately help scientists better understand a species that is so unlike our own when it comes to infant development. Wendy and Allison hope to eventually document and share their findings with others to increase the body of knowledge out there and help shape best practices when it comes to the care of these fascinating animals.